the average life span was almost 40. 50 years later, 47. by 1950, it was up to 68. now, the average in america is 78. 76 for men and 81 for women. the numbers will only go up. and up. the. >> their of a book called "100 plus, the coming age of longevity will change everything." everything? >>guest: everything. >> how much longevity? >>guest: i take the premise it will be possible in for average life expectancy to go up to 150. >> there is someone alive today who will live to be 150? >>guest: absolutely. >> is that creepy? you will be shriveled? >>guest: no, we will be healthier for longer, and energetic and enjoying likes. >> because they invent body part replacements. >>guest: that is a low-hanging fruits. scientists have created brand new humoring begans using a person's adult stem cells so bladders, trachea, human blood vessels, they have been created already. >> so, assume we accept this, we are healthy, what happens to your life? you work longer? you change jobs? don't you get sick of it? >>guest: the exiting is, there will be much more opportunity. right now, with the average life span o